This is precisely one of the best things about AVG. It works completely in the background, without the need of half the system resources and of course, without constantly bothering you with warning windows or update messages. You can just go on with your work and you won't even notice you have an antivirus application up and running. Being the free version of a complete program, AVG shows the odd nagging notification encouraging you to buy AVG Professional which may annoy the more sensitive users